The invention relates to a pyrotechnic actuator assembly for release of a retaining means in a vehicle safety system as well as an airbag module of a vehicle safety system comprising such actuator assembly.
In engineering, for example also in vehicle safety engineering, explosive studs are used as actuator units. As a rule, they are extremely robust metallic components adapted to be fastened via a thread and to absorb very high forces. Correspondingly high is the required activating energy of these explosive studs so that they expose housing apertures, for example, displace components (sometimes against a compressive force) or break them into preferably two fragments, i.e. so-to-speak cut themselves through.
In current vehicle safety systems, especially in the case of airbag modules, it is endeavored to adapt the safety system more and more individually to different parameters of a crash situation. A known and advantageous possibility is the use of retaining means such as tethers by release of which discharge orifices are opened or closed. By means of such retaining means also the airbag geometry can be alternatively or additionally influenced and/or an additional airbag volume can be released.
For active release of the tethers a tether activation unit “TAU” as it is called is required. Said TAUs are usually shear-stressed by comparatively low transverse force loads.
Conventional explosive studs are frequently over-dimensioned and too expensive for these applications.
For this reason, in DE 10 2005 058 721 A1 already pyrotechnic actuator units which have a plastic housing and therefore can be manufactured at reasonable cost are disclosed for actuation of a vehicle safety system.
In DE 10 2005 058 721 A1 a prefabricated already independently tested (“qualified”) pyrotechnic igniter is used which has to be supplied as separate component during manufacture of an actuator unit. This prefabricated component is then accommodated in a housing, especially a plastic housing, the housing including a portion for fixing the retaining means and a detent portion for fastening the actuator unit. After manufacturing the pyrotechnic actuator unit, it has to be tested and qualified again, before it can be mounted in a vehicle safety system.